Recoil Reducing Spring System

ABSTRACT

A firearm comprising a receiver with a bolt carrier assembly, a buttstock having a tube shaped opening adjacent to the rear of the bolt carrier assembly, a plurality of springs having similar inside and outside diameters disposed end-to-end within the tube shaped opening, and a buffer having a small diameter body disposed inside the inner diameter of the springs and having a large diameter head disposed where the foremost spring presses against the rear of the head and the front of the head presses against the rear of the bolt carrier assembly.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No. 61/752,387 filed on Jan. 14, 2013 which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates in general to firearms and more particularly to recoil reducing mechanisms within firearms.

BACKGROUND OF THE INVENTION

A challenging problem that has plagued firearms from their inception is how to control recoil forces generated by the chemical reaction which propels projectiles. Firearm recoil can lead to discomfort and injury to the shooter who must maintain control of the firearm. Recoil also causes undesirable muzzle lift when a firearm is prevented from naturally moving backward. This muzzle lift prevents accurate firing unless the shooter waits long enough to restablilize the firearm thereby slowing the shooter's rate of fire. Minimizing the negative effects from recoil has been complicated by modern firearms which use recoil forces to extract spent cartridge cases and load successive rounds. In such firearms, altering the recoil characteristics can result in failed extraction and loading which would potentially jam the firearm.

Popular modern firearms that operate in this fashion include the M16 family which encompasses the AR-15. Firearms in the M16 family use a bolt carrier to extract spent cartridges and strip successive cartridges from a magazine and into battery position. As the bolt carrier is pushed rearwards by gases produced from burning gun powder, it extracts spent cartridge casings. To accommodate the space needed for the bolt carrier's rearward movement, a buffer tube located in the stock is positioned directly behind and in-line of the bolt carrier and barrel. Within the buffer tube, and pressed against the rear of the bolt carrier, is a metal buffer which limits the bolt carrier's rearward travel. Unimpeded, the bolt carrier and buffer would slam into the rear of the buffer tube, transferring an enormous amount of energy into the stock, making it very difficult to control the firearm. To soften this buffer to buffer tube collision, many firearms, including the M16 family, use a buffer spring located within the buffer tube to slow the rearward motion of the bolt carrier. The recoil force absorbed in the buffer spring is then released as the buffer spring pushes the buffer and bolt carrier forward striping the next round from the magazine and into battery position to fire again.

Despite the inclusion of the buffer spring to slow and soften buffer to buffer tube contact, there is still an undesirable amount force transferred to the firearm when the buffer slams into the rear of the buffer tube resulting in significant recoil felt by the shooter and attendant muzzle lift. Various improvements to the recoil system used in such firearms have been proposed in the past. Most of these proposed improvements consist of replacing the factory metal buffer with another design to soften contact between the buffer and end of the buffer tube. These replacement buffers often comprise many more parts than the factory buffer, making them more expensive and unreliable, and only provide minimal recoil reduction. None of these proposed solutions improve on the single buffer spring used by the M16 family of firearms. Replacement single springs of slightly different spring rates are sold in the market, but these springs still have a linear rate which prevents any significant recoil reduction without compromising firearm reliability.

SUMMARY OF THE INVENTION

In accordance with the present invention, an apparatus is provided for nonlinear slowing of the bolt carrier and buffer of firearms, such as those used in the M16 family, which allows proper automatic extraction and loading of successive cartridges while reducing buffer to buffer tube impact, resulting in less recoil and muzzle lift. The apparatus replaces the factory single buffer spring with a spring system utilizing two or more springs with differing spring rates in series. The spring system replaces the factory single spring and fits within the buffer tube without modification to any parts of the firearm and allows full bolt carrier travel within the buffer tube to ensure proper firearm function. The springs used have outer and inner diameters that are similar to the factory buffer spring which permits the use of the factory buffer or any buffer with similar dimensions. By using two or more springs, the velocity of the bolt carrier can be controlled more precisely. In the interest of reducing buffer to buffer tube impact, the spring system can incorporate a stiff spring which absorbs more energy and slows the buffer more rapidly right before the buffer contacts the end of the buffer tube yet maintain proper firearm function by also having a softer spring in the system to ensure the bolt carrier assembly cycles properly. The resulting reduction in buffer to buffer tube impact lessens the amount of energy transferred to the rest of the firearm and shooter along with minimizing muzzle lift.

In the preferred embodiment, the recoil reducing spring system comprises two springs with a spacer placed between the springs. One of the springs in the system is longer with a softer spring rate in comparison to the other spring which is shorter and stiffer. This two spring system is assembled by placing the short spring into the buffer tube first such that the short spring's proximal end rests against the rear of the buffer tube. The spacer is then inserted into the buffer tube touching the distal end of the short spring. Finally, the long spring is inserted into the buffer tube such that the long spring's proximate end rests against the spacer and the distal end touches the buffer head. The springs and spacer comprising the recoil reducing spring system share the similar inside and outside diameters to fit within the buffer tube and allow the buffer to travel through the center of the recoil reducing spring system without binding as the springs compress and decompress.

In operation, the recoil reducing spring system begins to compress as the bolt carrier is forced rearward. The long spring compresses initially due to its softer spring rate which begins to slow the bolt carrier's motion as the bolt carrier's kinetic energy is converted into potential energy in the long spring. The short spring's stiffer spring rate serves to slow the bolt carrier at a faster rate just before the buffer collides with the buffer tube end. Thus the buffer's impact energy is reduced which results in less energy transferred to the rest of the firearm and to the shooter as well as reducing muzzle lift. After the buffer contacts the end of the buffer tube, the short spring decompresses as the potential energy in the short spring is converted back into kinetic energy which accelerates the bolt carrier forward. After the short spring decompresses, the long spring will decompress as well, moving the bolt carrier the rest of the way back into battery position.

Other advantages and features of the invention will become apparent from the following detailed description of its specific embodiment, with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a side view, partially cut away, of a firearm containing the recoil reducing spring system in accordance with an embodiment of the present invention.

FIG. 2 depicts an enlarged, partially cut away side view of a buttstock of a firearm containing the recoil reducing spring system in accordance with an embodiment of the present invention.

FIG. 3 depicts a side view of the recoil reducing spring system in accordance with an embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 illustrates a firearm 10 in the M16 family, such as an AR-15, shown from the side comprising a receiver 12 with a buttstock 14 attached to the rear of the receiver 12. The buttstock 14 contains a buffer tube 16 having a closed end 18 and an open end 20 which is shown cut away in FIGS. 1 and 2. The buffer tube 16 is attached to the receiver 12 at its open end 20. Contained within the buffer tube 16 is a buffer 22 along with the preferred embodiment of the recoil reducing spring system comprising: a short spring 24, a spacer 26, and a long spring 28. The buffer 22 comprises a small bumper end 30, a buffer body 32, and a larger stepped end 34 that is positioned within the long spring 28 at the opposite end from the spacer 26. FIG. 3 illustrates the components contained within the buffer tube including: the short spring 24, the spacer 26, the long spring 28, and the buffer 22.

The short spring 24, spacer 26, and long spring 28, which comprises the recoil reducing spring system, all have an outside diameter that is less than the inside diameter of the buffer tube 16 and an inside diameter that exceeds the outside diameter of the buffer bumper end 30 and buffer body 32 but not the stepped end 34. Having these dimensions, the recoil reducing spring system fits within the factory buffer tube 16 without modification and allows the bumper end 30 and buffer body 32 to pass longitudinally through the center of the recoil reducing spring system as the short spring 24 and long spring 28 compress and decompress thus maintaining proper firearm 10 function.

The recoil reducing spring system is installed by first inserting the short spring 24 into the buffer tube 16 through the open end 20 and sliding it down until it rests against the closed end 18. The spacer 26 is then inserted and rests against the short spring 24. The long spring 28 is inserted and rests against the spacer 26. Finally, the buffer 22 is inserted into the long spring 28 with the bumper end 30 first which places the bumper end 30 inside the long spring 28 with the stepped end 34 resting against the long spring 28.

The invention has been described in only one embodiment. It should be apparent to those skilled in the art that the invention is not so limited, but susceptible to various changes and modifications without departing from the spirit of the invention. 

The invention claimed is:
 1. A firearm comprising: a receiver; a bolt carrier assembly disposed within the receiver; a buttstock attached to the rear of the receiver, the buttstock having a generally tubular shaped opening adjacent the rear of the bolt carrier assembly; a plurality of springs disposed within the tubular opening of the buttstock; and a buffer having a head at one end and a body wherein the head is larger than the body where the body fits within the plurality of springs and the foremost spring rests against the rear of the head and the front of the head rests against the rear of the bolt carrier assembly.
 2. The firearm of claim 1 further comprising a means of separating the springs.
 3. The firearm of claim 1 wherein the plurality of springs is arranged in series.
 4. The firearm of claim 1 wherein the plurality of springs have outside diameters that are less than the inside diameter of the tubular opening and where the plurality of springs have inside diameters that are greater than the outside diameter of the buffer body.
 5. The firearm of claim 1 wherein two springs are disposed within the tubular opening of the buttstock in series.
 6. The firearm of claim 1 wherein the firearm is any firearm within the M16 family of firearms.
 7. The firearm of claim 1 wherein the firearm is an AR15.
 8. A firearm comprising: a receiver; a bolt carrier assembly disposed within the receiver; a buttstock attached to the rear of the receiver, the buttstock having a generally tubular shared opening adjacent the rear of the bolt carrier assembly; a first spring disposed within the tubular opening of the buttstock; a second spring disposed within the tubular opening of the buttstock forward of the first spring; and a buffer having a head at one end and a body wherein the head is larger than the body where the body fits within the long spring and the short spring and where the long spring rests against the rear of the head and the front of the head rests against the rear of the bolt carrier assembly.
 9. The firearm of claim 8 further comprising a means for separating the first spring from the second spring.
 10. The firearm of claim 8 wherein the first and second springs are different lengths.
 11. The firearm of claim 8 wherein the first spring and the second spring have outside diameters that are less than the inside diameter of the tubular opening and where the first spring and second spring have inside diameters that are greater than the outside diameter of the buffer body.
 12. The firearm of claim 8 wherein the first spring and the second spring have different spring rates.
 13. The firearm of claim 8 wherein the firearm is any firearm within the M16 family of firearms.
 14. The firearm of claim 8 wherein the firearm is an AR15.
 15. A firearm comprising: a receiver; a bolt carrier assembly disposed within the receiver; a buttstock attached to the rear of the receiver, the buttstock having a generally tubular shaped opening adjacent the rear of the bolt carrier assembly; a short spring disposed within the tubular opening of the buttstock; a long spring disposed within the tubular opening of the buttstock forward of the short spring; a means for separating the short spring and the long spring disposed between the short spring and the long spring; and a buffer having a head at one end and a body wherein the head is larger than the body where the body fits within the long spring and short spring and where the long spring rests against the rear of the head and the front of the head rests against the rear of the bolt carrier assembly.
 16. The firearm of claim 15 wherein the means for separating the short spring and the long spring comprises a disc shaped spacer having a concentric hole with a diameter larger than the outside diameter of the buffer body.
 17. The firearm of claim 15 wherein the short spring and the long spring have outside diameters that are less than the inside diameter of the tubular opening and where the short spring and long spring have inside diameters that are greater than the outside diameter of the buffer body.
 18. The firearm of claim 15 wherein the short spring and long spring have different spring rates.
 19. The firearm of claim 15 wherein the firearm is any firearm within the M16 family of firearms.
 20. The firearm of claim 15 wherein the firearm is an AR15. 